King Charles came face to face with his own face on the new banknotes which will go into circulation in June.
At Buckingham Palace, the King was presented with the first of the new £5, £10, £20 and £50 banknotes which will show his portrait.
It follows the tradition of the monarch receiving the first issues of new banknotes.
The existing banknotes, from the reign of Queen Elizabeth II, will continue to be used alongside the new notes.
King Charles has not been taking part in big public engagements since his cancer diagnosis, but has continued with private events such as this meeting, where he was shown the banknotes by Andrew Bailey, governor of the Bank of England.
Mr Bailey told the King that this was the first time that the Bank of England had had to change the monarch on the banknotes - as the late Queen Elizabeth II had been the first monarch to have her portrait on all of the Bank of England's banknotes.
The King, given a set of notes with 00001 serial numbers, described the design as "very elegant".
The new polymer banknotes show an engraving of King Charles based on a picture taken in 2013. Unlike the notes of his mother's reign, the King isn't wearing a crown.
The banknotes mark one of the last major steps of the transition to the reign of King Charles, with new stamps and coins already in circulation.
The Bank of England says there will be a gradual introduction for the King Charles banknotes, with the current Queen Elizabeth notes being used until they become worn or damaged.
So even though the new notes are being launched on 5 June, it could be some months before people see them in regular circulation, says the bank.
The trend towards cashless payments could also mean that the change in notes is not so immediately visible.
The first new banknotes were printed last year, with the long lead-in time allowing automated machines that accept cash to be updated to recognise the new designs.
